Bounded Rationality,Group Formation and the Emergence of Trust: An Agent-Based Economic Model

Computational Economics - It is possible to model trust as an investment game, where a player in order to receive a reward or a better outcome, accepts a certain risk of defection by another...     

Revolving Vernier Mechanism Controls Size of Linear Homomultimer

A new kind of the Vernier mechanism that is able to control the size of linear assembly of DNA origami nanostructures is proposed. The mechanism is realized by mechanical design of DNA origami, which consists of a hollow cylinder and a rotatable shaft in it connected through the same scaffold. This nanostructure stacks with each other by the shape complementarity at its top and bottom surfaces of the cylinder, while the number of stacking is limited by twisting angle of the shaft. Experiments have shown that the size distribution of multimeric assembly of the origami depends on the twisting angle of the shaft; the average lengths of the multimer are decamer, hexamer, and tetramer for 0°, 10°, and 20° twist, respectively. In summary, it is possible to affect the number of polymerization by adjusting the precise shape and movability of a molecular structure.     

Broadband Tuning of a Continuous-Wave, Doubly Resonant, Lithium Triborate Optical Parametric Oscillator from 791 to 1620 nm

We report the use of extreme broadband, high reflectivity >99.5%, optical parametric oscillator (OPO) cavity mirrors. A continuous-wave, doubly resonant, OPO demonstrated tuning over a range of 791-1620 nm with a single mirror set. Wavelength tuning was performed by temperature tuning the nonlinear material of lithium triborate. Narrow linewidth oscillation was confirmed throughout the tuning range, and threshold pump power increased gradually from 50 mW near the degeneracy to 800 mW at the tuning band edge in a double-pass pumping configuration.     

Geometrical analysis and design of a motion transmitting element for mobile vehicles

The range of speed or torque of motors is limited to some degree. Industrial vehicles working in factories are required to output a large force when they carry loads, and also to move with high velocity when they move to their destination. However, it is impossible to realize both those requirements if a conventional reduction device is used. Velocity variation devices using gears are widely used to change the velocity ratio between the input and output shafts. However, the motion transmission from the input shaft to the output shaft is interrupted during the velocity ratio variation process. In order to solve this problem, a velocity variation method that can transmit motion continuously is proposed, in which a motion transmitting element is used. In this report, a motion transmitting element using the geometrical analysis method is proposed, a method of expressing the curve using dispersed points is proposed, and a method of calculating the inclination and the distances along the curve is developed. Based on the proposed methods, the geometrical form of the transmitting element is analyzed.     

A biped static balance control and torque pattern learning under unknown periodic external forces

This paper addresses a biped balancing task in which an unknown external force is exerted, using the so-called ‘ankle strategy’ model. When an external force is periodic, a human adaptively maintains the balance, next learns how much force should be produced at the ankle joint from its repeatability, and finally memorized it as a motion pattern. To acquire motion patterns with balancing, we propose a control and learning method: as the control method, we adopt ground reaction force feedback to cope with an uncertain external force, while, as the learning method, we introduce a motion pattern generator that memorizes the torque pattern of the ankle joint by use of Fourier series expansion. In this learning process, the period estimation of the external force is crucial; this estimation is achieved based on local autocorrelation of joint trajectories. Computer simulations and robot experiments show effective control and learning results with respect to unknown periodic external forces.     

New pixel driving circuit using self‐discharging compensation method for high‐resolution OLED micro displays on a silicon backplane

A new 4T2C pixel circuit formed on a silicon substrate is proposed to realize a high‐resolution 7.8‐μm pixel pitch AMOLED microdisplay. In order to achieve high luminance uniformity, the pixel circuit compensates its Vth variation of the MOSFET for the driving transistor internally by using self‐discharging method. Also presented are 0.5‐in Quad‐VGA and 1.25‐in wide Quad‐XGA microdisplays with the proposed pixel circuit.     

A study on a quantum-inspired evolutionary algorithm based on pair swap

A quantum-inspired evolutionary algorithm (QEA) is proposed as a stochastic algorithm to perform combinatorial optimization problems. The QEA is evolutionary computation that uses quantum bits and superposition states in quantum computation. Although the QEA is a coarse-grained parallel algorithm, it involves many parameters that must be adjusted manually. This paper proposes a new method, named pair swap, which exchanges each best solution information between two individuals instead of migration in the QEA. Experimental results show that our proposed method is a simpler algorithm and can find a high quality solution in the 0-1 knapsack problem. This work was presented in part at the 12th International Symposium on Artificial Life and Robotics, Oita, Japan, January 25–27, 2007     

Bottom-up pyramid cellular acceptors with three-dimensional layers

In 1997, C.R. Dyer and A. Rosenfeld introduced an acceptor on a two-dimensional pattern (or tape), called the pyramid cellular acceptor, and demonstrated that many useful recognition tasks are executed by pyramid cellular acceptors in time proportional to the logarithm of the diameter of the input. They also introduced a bottom-up pyramid cellular acceptor which is a restricted version of the pyramid cellular acceptor, and proposed some interesting open problems of the bottom-up pyramid cellular acceptors. On the other hand, we think that the study of threedimensional automata has been meaningful as the computational model of three-dimensional information processing such as computer vision, robotics, and so forth. In this paper, we investigate about bottom-up pyramid cellular acceptors with three-dimensional layers, and show their some accepting powers. This work was presented in part at the 13th International Symposium on Artificial Life and Robotics, Oita, Japan, January 31–February 2, 2008     

Dynamic alternation of primate response properties during trial-and-error knowledge updating

Humans and animals seek appropriate solutions to novel problems through trial-and-error (TE) actions and observation of their outcomes. Once an individual has obtained the knowledge (rule) to solve a problem, knowledge-based (KB) actions may be applied in a stereotypical manner. Solutions can thus be based on TE or KB actions. To characterize this learning process at the behavioral level, we developed a new cognitive task for a laboratory monkey (Macaca fuscata) to perform. In this task, a search array consisting of six elements of different colors was presented, one of which was the behaviorally relevant target. The target color was changed unpredictably with no instruction or signal, requiring the monkey to use a TE search strategy to find the target color. We found that once the monkey identified the relevant color by chance after a color change, correct performance increased in a step-like manner and at the same time, other response properties (reaction time and color-choice tendency) also changed discontinuously. These step-like alternations in behavioral performance may be attributed to the subject’s switching between TE and KB search strategies in the two phases. The present study has therefore provided behavioral evidence for the timing and manner of switching between search strategies during the process of updating knowledge.